tools/iio/generic_buffer.c

   1 /* Industrialio buffer test code.
   2  *
   3  * Copyright (c) 2008 Jonathan Cameron
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is primarily intended as an example application.
  10  * Reads the current buffer setup from sysfs and starts a short capture
  11  * from the specified device, pretty printing the result after appropriate
  12  * conversion.
  13  *
  14  * Command line parameters
  15  * generic_buffer -n <device_name> -t <trigger_name>
  16  * If trigger name is not specified the program assumes you want a dataready
  17  * trigger associated with the device and goes looking for it.
  18  *
  19  */
  20
  21 #include <unistd.h>
  22 #include <stdlib.h>
  23 #include <dirent.h>
  24 #include <fcntl.h>
  25 #include <stdio.h>
  26 #include <errno.h>
  27 #include <sys/stat.h>
  28 #include <sys/dir.h>
  29 #include <linux/types.h>
  30 #include <string.h>
  31 #include <poll.h>
  32 #include <endian.h>
  33 #include <getopt.h>
  34 #include <inttypes.h>
  35 #include "iio_utils.h"
  36
  37 /**
  38  * size_from_channelarray() - calculate the storage size of a scan
  39  * @channels:           the channel info array
  40  * @num_channels:       number of channels
  41  *
  42  * Has the side effect of filling the channels[i].location values used
  43  * in processing the buffer output.
  44  **/
  45 int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
  46 {
  47         int bytes = 0;
  48         int i = 0;
  49
  50         while (i < num_channels) {
  51                 if (bytes % channels[i].bytes == 0)
  52                         channels[i].location = bytes;
  53                 else
  54                         channels[i].location = bytes - bytes%channels[i].bytes
  55                                 + channels[i].bytes;
  56                 bytes = channels[i].location + channels[i].bytes;
  57                 i++;
  58         }
  59         return bytes;
  60 }
  61
  62 void print2byte(uint16_t input, struct iio_channel_info *info)
  63 {
  64         /* First swap if incorrect endian */
  65         if (info->be)
  66                 input = be16toh(input);
  67         else
  68                 input = le16toh(input);
  69
  70         /*
  71          * Shift before conversion to avoid sign extension
  72          * of left aligned data
  73          */
  74         input >>= info->shift;
  75         input &= info->mask;
  76         if (info->is_signed) {
  77                 int16_t val = (int16_t)(input << (16 - info->bits_used)) >>
  78                               (16 - info->bits_used);
  79                 printf("%05f ", ((float)val + info->offset) * info->scale);
  80         } else {
  81                 printf("%05f ", ((float)input + info->offset) * info->scale);
  82         }
  83 }
  84
  85 void print4byte(uint32_t input, struct iio_channel_info *info)
  86 {
  87         /* First swap if incorrect endian */
  88         if (info->be)
  89                 input = be32toh(input);
  90         else
  91                 input = le32toh(input);
  92
  93         /*
  94          * Shift before conversion to avoid sign extension
  95          * of left aligned data
  96          */
  97         input >>= info->shift;
  98         input &= info->mask;
  99         if (info->is_signed) {
 100                 int32_t val = (int32_t)(input << (32 - info->bits_used)) >>
 101                               (32 - info->bits_used);
 102                 printf("%05f ", ((float)val + info->offset) * info->scale);
 103         } else {
 104                 printf("%05f ", ((float)input + info->offset) * info->scale);
 105         }
 106 }
 107
 108 void print8byte(uint64_t input, struct iio_channel_info *info)
 109 {
 110         /* First swap if incorrect endian */
 111         if (info->be)
 112                 input = be64toh(input);
 113         else
 114                 input = le64toh(input);
 115
 116         /*
 117          * Shift before conversion to avoid sign extension
 118          * of left aligned data
 119          */
 120         input >>= info->shift;
 121         input &= info->mask;
 122         if (info->is_signed) {
 123                 int64_t val = (int64_t)(input << (64 - info->bits_used)) >>
 124                               (64 - info->bits_used);
 125                 /* special case for timestamp */
 126                 if (info->scale == 1.0f && info->offset == 0.0f)
 127                         printf("%" PRId64 " ", val);
 128                 else
 129                         printf("%05f ",
 130                                ((float)val + info->offset) * info->scale);
 131         } else {
 132                 printf("%05f ", ((float)input + info->offset) * info->scale);
 133         }
 134 }
 135
 136 /**
 137  * process_scan() - print out the values in SI units
 138  * @data:               pointer to the start of the scan
 139  * @channels:           information about the channels. Note
 140  *  size_from_channelarray must have been called first to fill the
 141  *  location offsets.
 142  * @num_channels:       number of channels
 143  **/
 144 void process_scan(char *data,
 145                   struct iio_channel_info *channels,
 146                   int num_channels)
 147 {
 148         int k;
 149
 150         for (k = 0; k < num_channels; k++)
 151                 switch (channels[k].bytes) {
 152                         /* only a few cases implemented so far */
 153                 case 2:
 154                         print2byte(*(uint16_t *)(data + channels[k].location),
 155                                    &channels[k]);
 156                         break;
 157                 case 4:
 158                         print4byte(*(uint32_t *)(data + channels[k].location),
 159                                    &channels[k]);
 160                         break;
 161                 case 8:
 162                         print8byte(*(uint64_t *)(data + channels[k].location),
 163                                    &channels[k]);
 164                         break;
 165                 default:
 166                         break;
 167                 }
 168         printf("\n");
 169 }
 170
 171 void print_usage(void)
 172 {
 173         printf("Usage: generic_buffer [options]...\n"
 174                "Capture, convert and output data from IIO device buffer\n"
 175                "  -c <n>     Do n conversions\n"
 176                "  -e         Disable wait for event (new data)\n"
 177                "  -g         Use trigger-less mode\n"
 178                "  -l <n>     Set buffer length to n samples\n"
 179                "  -n <name>  Set device name (mandatory)\n"
 180                "  -t <name>  Set trigger name\n"
 181                "  -w <n>     Set delay between reads in us (event-less mode)\n");
 182 }
 183
 184 int main(int argc, char **argv)
 185 {
 186         unsigned long num_loops = 2;
 187         unsigned long timedelay = 1000000;
 188         unsigned long buf_len = 128;
 189
 190         int ret, c, i, j, toread;
 191         int fp;
 192
 193         int num_channels;
 194         char *trigger_name = NULL, *device_name = NULL;
 195         char *dev_dir_name, *buf_dir_name;
 196
 197         int datardytrigger = 1;
 198         char *data;
 199         ssize_t read_size;
 200         int dev_num, trig_num;
 201         char *buffer_access;
 202         int scan_size;
 203         int noevents = 0;
 204         int notrigger = 0;
 205         char *dummy;
 206
 207         struct iio_channel_info *channels;
 208
 209         while ((c = getopt(argc, argv, "c:egl:n:t:w:")) != -1) {
 210                 switch (c) {
 211                 case 'c':
 212                         errno = 0;
 213                         num_loops = strtoul(optarg, &dummy, 10);
 214                         if (errno)
 215                                 return -errno;
 216                         break;
 217                 case 'e':
 218                         noevents = 1;
 219                         break;
 220                 case 'g':
 221                         notrigger = 1;
 222                         break;
 223                 case 'l':
 224                         errno = 0;
 225                         buf_len = strtoul(optarg, &dummy, 10);
 226                         if (errno)
 227                                 return -errno;
 228                         break;
 229                 case 'n':
 230                         device_name = optarg;
 231                         break;
 232                 case 't':
 233                         trigger_name = optarg;
 234                         datardytrigger = 0;
 235                         break;
 236                 case 'w':
 237                         errno = 0;
 238                         timedelay = strtoul(optarg, &dummy, 10);
 239                         if (errno)
 240                                 return -errno;
 241                         break;
 242                 case '?':
 243                         print_usage();
 244                         return -1;
 245                 }
 246         }
 247
 248         if (device_name == NULL) {
 249                 printf("Device name not set\n");
 250                 print_usage();
 251                 return -1;
 252         }
 253
 254         /* Find the device requested */
 255         dev_num = find_type_by_name(device_name, "iio:device");
 256         if (dev_num < 0) {
 257                 printf("Failed to find the %s\n", device_name);
 258                 return dev_num;
 259         }
 260         printf("iio device number being used is %d\n", dev_num);
 261
 262         ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
 263         if (ret < 0)
 264                 return -ENOMEM;
 265
 266         if (!notrigger) {
 267                 if (trigger_name == NULL) {
 268                         /*
 269                          * Build the trigger name. If it is device associated
 270                          * its name is <device_name>_dev[n] where n matches
 271                          * the device number found above.
 272                          */
 273                         ret = asprintf(&trigger_name,
 274                                        "%s-dev%d", device_name, dev_num);
 275                         if (ret < 0) {
 276                                 ret = -ENOMEM;
 277                                 goto error_free_dev_dir_name;
 278                         }
 279                 }
 280
 281                 /* Verify the trigger exists */
 282                 trig_num = find_type_by_name(trigger_name, "trigger");
 283                 if (trig_num < 0) {
 284                         printf("Failed to find the trigger %s\n", trigger_name);
 285                         ret = trig_num;
 286                         goto error_free_triggername;
 287                 }
 288                 printf("iio trigger number being used is %d\n", trig_num);
 289         } else
 290                 printf("trigger-less mode selected\n");
 291
 292         /*
 293          * Parse the files in scan_elements to identify what channels are
 294          * present
 295          */
 296         ret = build_channel_array(dev_dir_name, &channels, &num_channels);
 297         if (ret) {
 298                 printf("Problem reading scan element information\n");
 299                 printf("diag %s\n", dev_dir_name);
 300                 goto error_free_triggername;
 301         }
 302
 303         /*
 304          * Construct the directory name for the associated buffer.
 305          * As we know that the lis3l02dq has only one buffer this may
 306          * be built rather than found.
 307          */
 308         ret = asprintf(&buf_dir_name,
 309                        "%siio:device%d/buffer", iio_dir, dev_num);
 310         if (ret < 0) {
 311                 ret = -ENOMEM;
 312                 goto error_free_channels;
 313         }
 314
 315         if (!notrigger) {
 316                 printf("%s %s\n", dev_dir_name, trigger_name);
 317                 /* Set the device trigger to be the data ready trigger found
 318                  * above */
 319                 ret = write_sysfs_string_and_verify("trigger/current_trigger",
 320                                                     dev_dir_name,
 321                                                     trigger_name);
 322                 if (ret < 0) {
 323                         printf("Failed to write current_trigger file\n");
 324                         goto error_free_buf_dir_name;
 325                 }
 326         }
 327
 328         /* Setup ring buffer parameters */
 329         ret = write_sysfs_int("length", buf_dir_name, buf_len);
 330         if (ret < 0)
 331                 goto error_free_buf_dir_name;
 332
 333         /* Enable the buffer */
 334         ret = write_sysfs_int("enable", buf_dir_name, 1);
 335         if (ret < 0)
 336                 goto error_free_buf_dir_name;
 337         scan_size = size_from_channelarray(channels, num_channels);
 338         data = malloc(scan_size*buf_len);
 339         if (!data) {
 340                 ret = -ENOMEM;
 341                 goto error_free_buf_dir_name;
 342         }
 343
 344         ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
 345         if (ret < 0) {
 346                 ret = -ENOMEM;
 347                 goto error_free_data;
 348         }
 349
 350         /* Attempt to open non blocking the access dev */
 351         fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
 352         if (fp == -1) { /* If it isn't there make the node */
 353                 ret = -errno;
 354                 printf("Failed to open %s\n", buffer_access);
 355                 goto error_free_buffer_access;
 356         }
 357
 358         /* Wait for events 10 times */
 359         for (j = 0; j < num_loops; j++) {
 360                 if (!noevents) {
 361                         struct pollfd pfd = {
 362                                 .fd = fp,
 363                                 .events = POLLIN,
 364                         };
 365
 366                         ret = poll(&pfd, 1, -1);
 367                         if (ret < 0) {
 368                                 ret = -errno;
 369                                 goto error_close_buffer_access;
 370                         } else if (ret == 0) {
 371                                 continue;
 372                         }
 373
 374                         toread = buf_len;
 375
 376                 } else {
 377                         usleep(timedelay);
 378                         toread = 64;
 379                 }
 380
 381                 read_size = read(fp,
 382                                  data,
 383                                  toread*scan_size);
 384                 if (read_size < 0) {
 385                         if (errno == EAGAIN) {
 386                                 printf("nothing available\n");
 387                                 continue;
 388                         } else
 389                                 break;
 390                 }
 391                 for (i = 0; i < read_size/scan_size; i++)
 392                         process_scan(data + scan_size*i,
 393                                      channels,
 394                                      num_channels);
 395         }
 396
 397         /* Stop the buffer */
 398         ret = write_sysfs_int("enable", buf_dir_name, 0);
 399         if (ret < 0)
 400                 goto error_close_buffer_access;
 401
 402         if (!notrigger)
 403                 /* Disconnect the trigger - just write a dummy name. */
 404                 ret = write_sysfs_string("trigger/current_trigger",
 405                                          dev_dir_name, "NULL");
 406                 if (ret < 0)
 407                         printf("Failed to write to %s\n", dev_dir_name);
 408
 409 error_close_buffer_access:
 410         if (close(fp) == -1)
 411                 perror("Failed to close buffer");
 412 error_free_buffer_access:
 413         free(buffer_access);
 414 error_free_data:
 415         free(data);
 416 error_free_buf_dir_name:
 417         free(buf_dir_name);
 418 error_free_channels:
 419         for (i = num_channels - 1; i >= 0; i--) {
 420                 free(channels[i].name);
 421                 free(channels[i].generic_name);
 422         }
 423         free(channels);
 424 error_free_triggername:
 425         if (datardytrigger)
 426                 free(trigger_name);
 427 error_free_dev_dir_name:
 428         free(dev_dir_name);
 429
 430         return ret;
 431 }